If all it took was a phone call and some cash to get things like the RPK74 drum mags, 60rd quad stack 74 mags, and Bizon drums then someone surely would have done so by now.

In theory, all you have to do is find someone with the mags to sell them to you, then get an approved Form 6 (import license) for them. In reality, there is a 1996 trade agreement with Russia in effect which prohibits the import of most milsurp arms items like parts kits and such. They specifically exempted the Saigas and a few other "commercial arms" which is why we can still get those, as well as ammo. IIRC, you have to provide proof any controlled Russian origin item has been out of that country several years before they can even be imported from a different country. Ask 4thIDVet about that, he tried getting some russian origin imports in from SE Asia a while back.....

In addition, Russia pissed off the US state department a while back by selling naughty toys to countries we don't play nice with, so they cut off the legal imports too. One of the reasons Saigas, Wolf, and other Russkie ammo disappeared for a while. Either those sanctions have been lifted or they found a workaround since the stuff is flowing again.

Maybe Comrad Chavez in Venezuela can crank out a few export mags and parts for the US market ??? No ??? He is getting a brand new AK plant installed down there. No wonder comrad Obamo is being nice to Hugo these days.

I got out a ruler and did some experimenting with my AK. A buttplate, a 12+ inch mag, and space for my wrist moved the rear grip pretty far forward, even for my apelike arms. I punted and ordered the 50-round mag.

Looks like the short magazine will be perfect. Length is
7-1/4", but the diameter is less than I thought - only 2-1/4".
It's about the same size as some of those "energy drinks" in
the aluminum cans, or maybe a large pepper grinder.

If you want to flip the cartridges around to feed Bizon style, you *might* be able to grind a bit and make it work, but it looks like you'd need to grind the existing feed lips away and make a 1/4" or 3/8" high tower. The plastic magazine is plenty thick; I'd figure two or three 8-32 screws on each side would be sufficient.

The end of the magazine is relieved slightly so the cartridge doesn't have to pop all the way out the top before the bolt strips the cartridge off; that's why a short tower would be handy if you were stripping in the opposite direction.

The Calico mag is kindasorta octagonal, with thick longitudinal ribs, and looks nothing like a smooth Bizon mag, though as I mentioned earlier a little cosmetic work might make it a bit more similar.